The prior art is already aware of the formation of tracks in crawler tractors, and it is also aware of various arrangements for constructing joints which secure the links of track elements together in an endless manner. Still further, the prior art discloses many different arrangements of seals and also bushings which are utilized in articular joints, including the joints of a track in a crawler tractor. Examples of some of the prior art arrangements are found in U.S. Pat. Nos. 3,341,259 and 3,347,602 and 3,595,572 and 3,622,165 and 3,680,924. These prior art patents show arrangements of links and joints and seals, all of which are shown in the environment of an endless track for a crawler tractor.
The present invention provides an improvement over these prior art arrangements, and, more particularly, it provides a combined track seal and bushing which keeps the joint clean and which retains the lubrication in the joint and which also lessens and dampens noise otherwise created by the movement of the links forming the joint. Still further, the present invention provides a joint which minimizes wear on the parts of the joint which would otherwise be in contact with each other and which would be arranged to permit entrance of some amount of dirt into the joint and which would also permit the escape of some lubrication, all toward the undesirable end of causing undue wear and consequent looseness and failure of the joint.
Still further, it is an object of this invention to provide a joint which has the aforementioned advantages and which accomplishes those advantages without any unduly complicated parts and with only a reasonable amount of expense and while providing a reliable and sturdy joint which will last for a long time. Still further, the joint of this invention is arranged so that it can be readily and easily assembled by utilizing conventional manners and equipment for assembling crawler tractor tracks, and therefore no special skills nor tools are required.
More specifically, the present invention provides a joint with a combined seal and bushing which does not permit the entrance of dirt or the like and which therefore does not have dirt rubbing on the parts which are in moving contact, and, consequently, the joint of this invention is more reliable and has a longer life compared to the joints of the prior art. Also, the parts forming the joint of this invention can be made and assembled with less clearance than the corresponding parts of the prior art, and, accordingly, the combined seal and bushing of this invention is subjected to less eccentric positioning and therefore less failure due to unloading of the seal surface itself and thus there is no tendency for the seal surface to become damaged and fail.
Still further, in accomplishing the aforementioned objectives and advantages, the present invention provides a joint with a combined seal and bushing which can be reliably arranged to be compressed between the parts forming the joint, and thus the combined seal and bushing member serves its functions of keeping the joint free from dirt and also tightening the joint and avoiding undue generation of noise and wear in the joint.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.